Q:I live in San Francisco right next to the Bay Bridge and have a very large roof deck. I am getting excellent results from my dwarf lemon and lime trees planted in large ceramic pots. In addition to those, I have a couple of rosebushes and seasonal vegetables like tomatoes, basil, lettuce, broccoli and Brussels sprouts, all with, in my opinion, decent to good results. I would lovea dwarf avocado tree. I mentioned the other plants in my garden to give you an idea of what has been successful.

Yes, there can be a bit of wind (nothing crazy), and the temperature can dip down to the high 30s, which is very rare for San Francisco, but it does happen. I have fantastic sun. I think I can manage a tree of maybe 8-10 feet; smaller is better. I promise to use a very large pot if necessary. What do you recommend? I have heard good things about the 'Bacon' variety.

A: It appears that you live in heaven and you're only short one angel. Avocados are not as well adapted to growing in containers as citrus or roses, but success is possible. An avocado should tolerate moderate wind and your lowest temperatures, and it will love the sunshine.

As to variety, 'Bacon' is one of the more frost-hardy types, able to take at least 28 degrees Fahrenheit, so it is often chosen by inland gardeners, near Sacramento, for example. Also, 'Bacon' is a medium tall tree, which means it grows to something like 30 feet.

Shorter varieties would be better for a container. For example, 'Holiday' is an attractive 10- to 12-foot-tall tree, hardy to 30 degrees, bearing large (18- to 24-ounce) fruit from Labor Day to New Year's. The fruit is the 'Hass' type, with a pebbly green skin that ripens off the tree to nearly black. Or consider 'Lamb Hass,' a similar-size tree, hardy to 26 degrees, bearing 10- to 18-ounce Hass-type fruit from April to November.

Use the largest container you can manage, such as a half-barrel. John Seeger of Four Winds Growers, a Northern California wholesale fruit nursery whose trees are available at many local nurseries, advises repotting to refresh the growing medium every 18 to 24 months. He advises that using a mix that includes top soil and compost, rather than a lighter potting mix, will let the tree be healthy a bit longer between repotting.

He is also experimenting with new kind of container, called a Geopot, which is made of woven polypropylene. Its advantage for any container plant is that it prevents roots from circling the surface of the root ball. Instead, when roots reach its porous sides and bottom, their tips die (called "air pruning"), so the plant grows more-useful new roots inside the root ball. This should delay the need for time-consuming repotting.

Geopots, made by a local company, are available in various sizes for different kinds of plants, including 10-, 15- and 20-gallon ones suitable for trees, at geoplanter.com or (800) 681-1757. They look like big bags, so you might want to set one in a larger, more decorative pot.

When you do transplant, be aware that avocado roots are fibrous and brittle, so you need to be very gentle with them. Never carry the plant by its trunk; always lift under the pot or root ball. When you plant an avocado, be careful not to bury the trunk any deeper than it was growing before. In fact, in a container you might want to set it an inch or two high and fill in the difference with mulch (making sure there is still some "head room" in the container above the mulch to fill with water before it soaks in).

Like citrus, avocados are susceptible to root rot in soggy soil, but should never be allowed to dry out. In containers they need consistent, frequent water, making sure that drainage is excellent. Use a citrus/avocado fertilizer at least four times a year. Avocado has fewer micronutrient deficiency issues than citrus, but if leaves of new growth are yellow, you can apply an iron chelate to the soil. The trees need little pruning, but you can pinch off growth at branch tips to shape the plant and limit size.

Much has been made of "A" and "B" type avocados, which pollinate each other because their flowers shift from male- to female-receptive at opposite times of day. However Four Winds Growers say that in California, mild temperatures in the spring flowering season interrupt the pattern so that male and female cycles overlap and avocados can self-pollinate. Because of this, I think you can succeed with only one avocado tree on your roof deck.